1. Field of the Invention
This invention relates to an edible emulsion having a much lower fat content than conventional emulsions, and to a method of making it. Such emulsions may for example be used for spreads to be used as alternatives for butter or margarine. Other possible uses include salad dressings to be used instead of mayonnaise or salad cream, and low fat desserts.
2. Description of the Prior Art
Conventional edible emulsions typically comprise a fat or oil phase dispersed in an aqueous phase, although other emulsions are known in which the fat or oil comprises the continuous phase and has the aqueous phase dispersed in it. The typical fat contents in conventional water-continuous emulsions ranges from about 80% down to 40%, and although it is in some cases regarded as desirable to reduce the fat content, it has been found difficult to produce a satisfactory emulsion having a fat content much below 20-25% since the fat or oil phase is necessary to impart the required flavour and texture.
Conventional edible emulsions of the type to which the invention relates generally include a small quantity of an emulsifier and well as protein or other dairy components, gelling agents, stabilizers, flavouring, colouring etc. Some typical compositions are disclosed in EP-A-463688, which discloses plastic edible emulsions in which the oil or fat component is dispersed in a continuous aqueous phase. Although the claimed range is 5 to 21 wt. %, the exemplified compositions contain 19.6 wt. % of palm mid-fraction as the fat component.
It is accordingly an object of the invention to provide an edible emulsion containing less than 5% by weight of oil or fat component.
According to the present invention this object is achieved by a low fat edible emulsion wherein less than 5 wt. % of fat or oil component is dispersed in water, together with a sufficient quantity of an emulsifier to impart the texture and flavour required of such an emulsion. It has been found that the emulsifier can work in synergy with the fat or oil component to impart a desirable texture and structure to the finished product with good spreading properties so that it resembles a product with a much higher fat content.
The edible emulsion of the invention comprises an aqueous dispersion of an edible fat or oil component and an emulsifier system. The fat or oil component is present in an amount less than 5 wt. %, based on the total emulsion, and the emulsifier system is a two-component or multi-component system which comprises a primary emulsifier comprising one or more components selected from proteins, skim milk powder, polysorbates, Datem, Citrem, sucrose esters, octenyl succinic acid (OSA) starches and gum arabic, acting to stabilise the emulsion, and a secondary emulsifier comprising one or more components selected from mono- and diglycerides, polysorbates, polyglycerol esters, organic acid esters of mono- and diglycerides, propylene glycol esters, stearyl lactylates, lecithin and sucrose fatty acid esters.
The aqueous phase of the composition may for example contain minor quantities of milk or other dairy components, bulking agents, gelling agents, starches and stabilizers. The oil phase comprises oils or fats which are edible and of the type generally used in the food industry.
Minor ingredients such as salt, phosphates, citrates, colouring, flavouring, vitamins, preservatives and food acids are also desirable components of the edible emulsions of the invention.
The secondary emulsifier is chosen from a group that is capable of creating this desirable texture and structure. These include mono- and diglycerides, polysorbates, polyglycerol esters, organic acid esters of mono- and diglycerides, propylene glycol esters, stearyl lactylates, lecithin and sucrose fatty acid esters. Especially useful are those emulsifiers which are prepared from unsaturated or partially unsaturated fats. The secondary emulsifier can be added as part of the fat or oil phase and by careful selection of the emulsifier type and grade, it can also be included as part of the aqueous phase.
While the inventors do not wish to be bound by any particular theory, the secondary emulsifier is believed to function by partly destabilising the oil in water emulsion to create a substantially semi-solid plastic matrix. The emulsion preferably contains from 0.2 to 2 wt. % of this secondary emulsifier.
Fats and oils can be selected from any suitable vegetable, animal or dairy source and include oils, hydrogenated and unhydrogenated fat as well as fractionated fats. The fat content is preferably at least 2 wt. %.
The oil in water emulsion is made by emulsifying the fat phase such that a dispersion of small uniform oil droplets is formed. This emulsification process can be enhanced by the use of a high pressure homogeniser, colloid mill, Silverson mixer or similar equipment together with the presence of the primary emulsifier. This agent has a function which is different from that of the aforementioned secondary emulsifier in that its primary role is to create a stable oil in water emulsion and is selected from proteins, especially caseinate and whey protein, skim milk powder and other materials which act as oil in water emulsifiers and include, but are not limited to, polysorbates, Datem, Citrem, sucrose esters, OSA starches and gum arabic. Certain emulsifiers, which include polysorbates, are multifunctional and provide the necessary oil in water emulsification. However, paradoxically they can also act to create a de-stabilisation of this emulsion. The total content of such emulsifying agents is preferably from 0.1 to 10 wt. %. Homogenization preferably takes place at a pressure of 2 to 50 MPa (20 to 500 bar), more preferably 5 to 20 MPa (50 to 200 bar).
The components which may be present in the aqueous phase include bulking agents such as maltodextrin, dairy proteins, inulin and polydextrose which are used together with thickeners and gelling agents. Thickeners include, but are not limited to, LBG, guar, xanthan alginate, Konjac, starches (native and modified), CMC, MCC. A typical composition may contain a total of 0.5 to 3 wt. % of these components.
Typical gelling agents include, but are not limited to, gelatin, carrageenan, alginate, pectin, gel forming starches or synergistic combinations of gums selected by those skilled in the art. The aqueous phase can be of a gelled nature or have enough viscosity to provide the body and structure into which the destabilised oil droplets is contained. The total content of these components is preferably 0.5 to 5 wt. %.
Heat treatment of the emulsion is desirable to confer microbiological stability to the product and for products which have a pH value of more than about 4 they are preferably heated to at least 80xc2x0 C. and preferably above 85xc2x0 C. A plate heat exchanger or scrape surface heat exchanger is suitable for this purpose. The product may be filled hot or cold. After filling the products are preferably stored under refrigeration.
The following formulations are shown to illustrate the invention: